Norton Jubilee 350
My riding pal had a Jubilee 250 with L plates. When the engine packed up he bought a spare for £10 took it home and fitted it into his frame. Then when he had finished he saw it was a 350cc motor. Swapped the 350 plate for his 250 plate and rode on with a 350 on L plates. Cool or what?

Around 1971, whilst out riding my superb Kawasaki Samurai, I pulled up alongside a brand new Commando at some traffic lights and heard a rough tick-over.

Taking a closer look, I saw petrol frothing out of a carb tickler and the engine wobbling like a jelly in the frame.

Jeez, those Commando designers were certainly skating on thin ice.

Give me a 650 Norton Mercury anyday over a Commando.

Generally speaking, the 'classic bike' scene has all the symptoms of a 'bubble' i.e. insane prices are being asked for grey porridge and even the rated stuff e.g. Vincents etc are IMHO, way over-priced.

it all went down the pan
when japs sussed engeneering.................i aint got any tech info to show but remember my ol man showing me the difference in running tolerances..............no wonder our british bikes rattled themselves to death" />

To be fair, I've just looked at his eBay ad and £4100 is not over-the-top by the standards of the current classic bike bubble.

Also, if you bought the bike, rode it very gently and kept it up together, you'd probably get your money back in a few years time.

PS. MCN readers who take an interest in the staffers bikes might have noticed that the only bike that has not only not lost any money but actually gained in value is a Norton 500T, whch the staffer paid £2000 for and is now worth about £5000.

Motorcycle designer Bert Hopwood came up with the original 500cc Norton Dominator engine.

In his book 'Whatever happened to the British motorcycle Industry', Bert says he was very disturbed to see that his original engine was stretched and stretched again from 500 to 600 to 650 to 750 and finally 850cc.

Dr Stefan Bauer, mining a rich seam of fundamental engineering principles (as
opposed to sitting back on decaying racing laurels), was unhappy with the
Featherbed and was quick to point out a number of its failings---not least that it
did little to soak up the crippling vibrations pulsing out from every stroke of
the Atlas's crank; vibes that were becoming increasingly problematic as Bert
Hopwood's original 500cc design had been blown out of all practical proportions
and had therefore became something of a Frankenstein's monster.

These vibes, opined Bauer, could
however be tamed/minimised with a new chassis; a chassis that would dangle the
engine, gearbox and driveline from a single top tube and would control lateral
(sideways) movement by a trio of rubber bushes placed at the top, front, and
underneath. Torsional (or twisting) stresses would be largely controlled by the
top tube itself. The trick was to allow the engine/gearbox/driveline sufficient
fore and aft movement, but without allowing it to transmit the bruising
vibrations through to the rider.

Exactly how much each member of the
team contributed to this new "Isolastic" design isn't clear. Suffice to say that
between these highly talented engineers came the 750cc Norton Commando, claimed
by some to be the finest British parallel twin ever, bar none.

The bugbear with this
Isolastic system, however, lay in the adjustment. Each rubber bush required
careful and precise---and difficult---shimming. If too tight, the
engine/gearbox/driveline would lock solid and send the vibes straight into the
chassis. If too loose, the lateral movement would become uncontrollable and
potentially dangerous.

But what's with this driveline
business, anyway? That's simple. Merely containing the engine and (pre-unit)
gearbox between three rubber mounts would leave these components pulling against
the drivechain when under load. That in turn would overstress the rubber bushes
creating various action/reaction problems. The solution, therefore, was to mount
the swinging arm (and therefore the driveline) directly to the gearbox
and suspend that with the three rubber mounts and the shock
absorbers.

And it worked. Moreover, isolating
the engine from the rider effectively liberated a lot of otherwise inhibiting
power.

The bugbear with this
Isolastic system, however, lay in the adjustment. Each rubber bush required
careful and precise---and difficult---shimming. If too tight, the
engine/gearbox/driveline would lock solid and send the vibes straight into the
chassis. If too loose, the lateral movement would become uncontrollable and
potentially dangerous.

But what's with this driveline
business, anyway? That's simple. Merely containing the engine and (pre-unit)
gearbox between three rubber mounts would leave these components pulling against
the drivechain when under load. That in turn would overstress the rubber bushes
creating various action/reaction problems. The solution, therefore, was to mount
the swinging arm (and therefore the driveline) directly to the gearbox
and suspend that with the three rubber mounts and the shock absorbers.

There was little time to
develop a brand new engine (Norton had already been struggling with an earlier
double overhead cam twin project known as P10, but had failed to make it sing
and dance). The only real option, it was suggested, was to rework the existing
745cc Atlas powerplant---with a reputation for serious vibration.

Buying a Japanese bike does not guarantee a trouble free motorcycling life.

For example, a fellow apprentice became utterly distraught every time his Honda CB250 (the original red/white K0 model from 1969/70) needed yet another carb diaphram, as it had split, and Honda were taking most of his miserly apprentice wages; who was so turned off by the experience that as soon as he passed his test,he bought a new Triumph T100.

Nobody can ever forget the total disaster that the early Honda V4's were and much more recently we have had the dubious saga of the ST1300 weave, (which has apparently been 'magically' fixed from 2008 onwards).

Yamaha, Suzuki and Kawasaki have also all had their share of clunkers over the years. Only Bridgestone's were practically faultless and the other four soon forced them out of the motorcycle business.

The only sensible advice seems to be to wait for a year or two when a new model comes out and see if any problems surface.

Having said that, I ignored that advice when the Honda ST1100 came out in 1989/90 and I'm still riding it today.

PS. Also, it is entirely possible for a bike to be a very good model at the outset and then 'go bad'. For example, the admirable little Honda CG125 went off the rails in 2004, when inexplicably (according to its Wiki entry) , Honda, revised the model and dumped the fully enclosed final drive. Doh! Or production of a previously sound Japanese motorcycle model shifts to another country and quality problems then begin to surface, which has happened.

**642 quid **
too much if you ask me, for a bike that shook like a shitting dog, how can they increase in value when in the first place they were absolute total shite, no wonderb the japanese suffocated the life out of the brit bike industry when they produced shite like those things.

I had already had lots of 'experience' with British bikes and I recall walking straight past the Commando to drool over a 650cc Mercury, being very lonely tucked in away in a corner.

I even got a sales leaflet for the Mercury and quite envy a chap in Australia who bought one brand new and which is still giving him good service today, some 44 years later.

Somehow, the Commando must have tapped into something in the typical British bikers mindset or it would'nt have kept winning that MCN poll year after year.

Presumably that long dormant ideal is the reason for the latest Commando - a new design - a very tough thing to succeed at but Bloor managed it with Triumph so maybe Garner and his people have a chance.